In this specification, the words deceth (1-5) sulfate, laureth (0-5) sulfate, etc., are used to describe the neutralized salt of the sulfuric half ester of the reaction product of decanol, lauryl alcohol, etc., with an average of 1-5 or 0-5 moles of ethylene oxide. The words decyl monoethoxy sulfate and lauryl diethoxy sulfate are used to describe the essentially pure compounds.
Hair conditioning compositions are often used after shampooing in order to make the hair more manageable and to facilitate both wet combing and dry combing. While a great variety of ingredients have been used for the purpose of conditioning, cationic surfactants are among the most generally used materials, with the mono-C.sub.12 -C.sub.18 alkyl quaternary ammonium salts being found in most of the popular hair conditioning products.
Typically, the conditioning compositions which utilize the mono-C.sub.12 -C.sub.18 alkyl quaternary conditioner contain from 1% to 6% by weight of the quaternary conditioner. This conditioner is effective because it is adsorbed by the hair. However, as some interaction occurs between the hair and the mono-alkyl quaternary ammonium conditioner, it has been noted that often not all of the conditioner is removed when the hair is subsequently shampooed. The build up of conditioner causes the hair to appear dull, i.e., not shiny and can also lead to hair that is limp and less manageable. More specifically, it has been discovered that shampoos containing lauryl sulfate and/or laureth (1-5) sulfate detergents--the primary detergent ingredients in most shampoos--do not copletely remove the mono-C.sub.18 alkyl quaternary ammonium conditioners from the hair. Additionally, it has been discovered that lauryl and/or laureth (1-5) sulfate detergents combine with the mono-C.sub.12 -C.sub.18 quaternary ammonium conditioners to form a water-insoluble complex that can build up on the hair with repeated shampoo and conditioner applications. Furthermore, no patents on the shampoos were noted in which the chain length of the alkyl group on the anionic alkyl sulfate and alketh (1-5) sulfate detergents averaged less than 12 carbon atoms.
In reviewing the patent literature for alternatives to shampoos containing a lauryl sulfate or a laureth (1-5) sulfate salt as the principal detergent, U.S. Pat. No. 3,775,349 was noted. This patent confirms that the optimum chain length for the anionic alketh (0-5) sulfate detergents is twelve carbons and that a typical distribution for such detergents which are based upon mid-cut coconut alcohols is 2% decyl, 66% dedecyl, 23% tetradecyl and 9% hexadecyl sulfate. The invention described in U.S. Pat. No. 3,775,349 is based upon the discovery that the foaming performance in dishwashing of C.sub.10 -C.sub.16 alketh (0-6) sulfates in hard water is improved when used in conjunction with a lauryl dimethyl amine oxide foam booster (5 detergent:1 amine oxide) at 0.45% concentration if from 10% to 50%, preferably 15% to 40%, by weight of deceth (3) sulfate is present in the formulation. In soft water, the presence of deceth (3) sulfate offers no advantage when present in amounts up to 35% by weight, but thereafter foaming performance is adversely affected, falling to 50% of the standard dishwashing formulation when 63% by weight of deceth (3) sulfates are present. Since the foaming performance of the inventive compositions was from 70% to 89% of the performance of a standard dishwashing detergent, this patent teaches away from the use of alketh (1-5) sulfate detergents containing more than 40% by weight of the corresponding deceth (3) sulfates.
Another patent noted was U.S. Pat. No. 4,024,078 which discloses liquid detergent compositions that are effective in cleaning dried on food soils from dishes and contain from 10% to 80%, preferably 15% to 60%, by weight of a mixture of decyl ethoxy and isopropoxy sulfates wherein at least 20% of said sulfates are mono-alkoxylated. Table II of this patent purports to show that decyl monoethoxy sulfate is superior in cleaning to the di-, tri,- tetra- and non-ethoxy sulfates of decyl alcohol when used in a formula containing, by weight, 25% of alkyl sulfate, 4% of sodium coconut glyceryl ether sulfonate, 5% coconut dimethyl amine oxide and the balance water, but the standard deviation of 0.6 for the cleaning scores shows that there is no significant difference in any of the cleaning scores presented. The indicated cleaning values show that decyl monoethoxy sulfate was equivalent in performance to dodecyl sulfate and tridecyl sulfate and inferior in performance to undecyl sulfate. Furthermore, the cleaning scores presented suggest that a mixture of dodecyl polyethoxy sulfates containing equal parts of 0, 1, 2, 3 and 4 ethenoxy groups would exhibit better cleaning performance than the same mixture of decyl polyethoxy sulfates. Thus, Table II suggests that the disclosed formulation containing pure decyl monoethoxy sulfate will be superior in cleaning to the same formula containing, for example, dodecyl monoethoxy sulfate or decyl diethoxy sulfate.
Table IV of the patent shows that the formulation in Table II containing decyl monoethoxy sulfate exhibits poorer sudsing in both hard and soft water than the same formulation containing dodecyl monoethoxy sulfate and that various mixtures of 10-30% decyl monoethoxy sulfate and 90-70% dodecyl monoethoxy sulfate in said formulation exhilitabout the same sudsing performance as the dodecyl monoethoxy sulfate. Additionally, Table III shows that the same formulation containing decyl triethoxy sulfate exhibits poorer foaming than said formulation containing dodecyl triethoxy sulfate. Thus, this patent teaches that a liquid formulation containing decyl monoethoxy sulfate is effective in removing a mixture of white milk and French's gravy from glasses and that the same formulation containing a mixture of 10-30% by weight of deceth (1-3) sulfate and 90-70% of dodeceth (1-3) sulfate is comparable in cleaning and sudsing to dodecyl triethoxy sulfate.
In view of the teachings of U.S. Pat. Nos. 4,024,078 and 3,775,349 it was surprising to discover that a hair cleaning composition containing a C.sub.6 -C.sub.10 alketh (1-5) sulfate as the principal detergent was more effective than the dodecyl sulfate or dodeceth (1-5) sulfate surfactant in removing a mono-C.sub.12 -C.sub.18 alkyl quaternary ammonium conditioner from the hair--a soil unlike the soils which are typically removed by liquid dishwashing compositions.